A major focus of Ahsoka Season 2 will be the master-and-padawan relationship between Ahsoka Tano and Sabine Wren, who were both stranded on Peridea after Grand Admiral Thrawn and Ezra Bridger escaped.
On one hand, Ahsoka and Sabine are left alone with a great opportunity to strengthen their strained bond; on the other, Shin Hati was abandoned by her master, Baylan Skoll, in the middle of nowhere. Skoll left her to pursue his own ambitions, and the finale showed how isolated and miserable Shin was because of her master's abandonment. Shin's future looks uncertain, while Ahsoka and Sabine seem to be on a collision course with her.
There's an uncanny similarity between Sabine and Shin, as both are complicated apprentices who must face the unknown. Dave Filoni may have interlocked their fates, which means that Ahsoka Tano could end up having to choose which one to save from the darkness that feeds on Peridea. What makes this intriguing is how much Shin needs a master like Ahsoka, who knows what it's like to be abandoned and who can recognize how vulnerable Shin is under her sad circumstances.

Why Shin is the apprentice Ahsoka deserves
While Sabine is a beloved character, she was developed so well and had such genuine relationships with other characters on Star Wars Rebels that her relationship with Ahsoka seems somewhat forced. Sabine is already a Mandalorian warrior from a planet with a rich history and a family that's well known among the elite Mandalorian clans. She had a personality long before Ahsoka, but her Force sensitivity is limited. In contrast, Shin Hati seems sheltered from much of the galaxy and has only followed Baylan Skoll her entire life, essentially making her a blank slate.
Baylan let her go when he had no use left for her, despite how promising she is. This is trauma Ahsoka can easily relate to. Ahsoka was framed for bombing the Jedi temple on Coruscant, and the council immediately abandoned her. Even after Anakin helped clear her name, Ahsoka couldn't tolerate the betrayal and decided to walk away from the Jedi. She understands what it's like to be alone. Her disillusionment with the Jedi Order made Ahsoka question her own allegiance for several decades. She never officially completed her training or called herself a Jedi.
She operated in a gray area between being a Jedi and just another Force user, which makes her the ideal master for Shin. Shin is just as unguided and lost, and redeeming a soul like her is a more satisfying narrative turn and a true test of Ahsoka's maturity and mastery of the Force. It would be up to Ahsoka to save Shin from the dark side, which would prey on her vulnerabilities in an isolated place like Peridea. This is more compelling than trying to train a Mandalorian warrior and forcing her into Jedi robes.

Why Ahsoka can only save one of them
Getting off Peridea won't be easy, and there's no guarantee Ahsoka, Sabine, and Shin can all survive the planet's darkness. Ahsoka already offered Shin her hand in season 1, which Shin refused. This means Shin may face a choice between the light and dark sides again, but this time, Ahsoka may have to choose whether to save Shin from the darkness that lurks on Peridea or to save Sabine.
Sabine leans closer to the light side of the Force, even though her choice to save Ezra Bridger may have unleashed havoc on the home galaxy. However, Shin is somewhere between the darkness and light, and abandonment from Baylan Skoll could push her closer to despair and, thus, complete corruption.
Saving one means leaving the other vulnerable to the planet's darkness. Star Wars has always been about balance, with a master devoted to one apprentice at a time. Can Ahsoka keep mentoring the willful Sabine Wren, or devote her spiritual energy to saving a lost Force wielder like Shin, whose fate, if left alone, could mirror Anakin's?
If Ahsoka tries to guide both, she may be forced to sacrifice one, as the balance between the light and the dark side on Peridea forces her to choose. The apparent rivalry between Shin and Sabine from season 1 may lead to the toughest decision of her life, one that determines who walks away from Peridea by her side.
